This invention relates to a bucket, for material handling apparatus of the kind including a bucket-supporting boom assembly disposed on a vehicle and projecting beyond one end thereof which assembly is so attached to the vehicle as to be pivotable relative thereto by power-operated means, said bucket being of the type having a back member adapted to be so mounted on the projecting end of the boom assembly as to be pivotable relative thereto by power operated means and a front member so mounted on the back member as to be pivotable relative thereto by power-operated means. The back member resembles a bulldozer blade, and the front member comprises two end plates welded to a bottom plate and resembles a backless bucket. The boom assembly may comprise twin booms disposed at opposite sides of the vehicle, in which case ground-engaging shoes may be provided on the projecting ends of the booms. Material handling apparatus comprising such a bucket and twin boom arrangement is disclosed in U.S. Pat. No. 2,812,595. Alternatively, the boom assembly may comprise a single boom arrangement. Said arrangement may be articulated, for example may comprise a first arm so attached to the vehicle as to be pivotable relative thereto by power-operated means and a second arm so attached to the free end of the first arm as to be pivotable relative thereto by power-operated means, the back member of the bucket being adapted to be mounted on the projecting end of the second arm.
Where a bucket of the type referred to is of considerable width, for example as shown in U.S. Pat. No. 2,812,595 of substantially the same width as the vehicle, it can perform in known manner a very large variety of operations including bulldozing and the like. The power-operated means for pivoting the front member relative to the back member have hitherto comprised two hydraulic piston-and-cylinder assemblies disposed at the respective ends of the bucket and fed from a common pressure line so as to work in unison. However, where an asymmetrical load has to be gripped between the front member and the back member, this arrangement suffers from the disadvantage that the front member is distorted due to the pressure liquid taking the path of least resistance and thus permitting unequal extension of said piston-and-cylinder assemblies.
The object of the present invention is to minimise the aforesaid disadvantage and at the same time reduce the cost of the bucket.